Saturday, October 27, 2012

Hamstring injuries prevention: an update

Last week I had the opportunity to attend the presentation by Professor Roald Bahr on recent evidence on hamstrings injury prevention. Professor Bahr is a leading sports medicine physician in the area with a lot of clinical and research work. I have coded the key points of his presentation by giving answers to the questions I assume most of us would have.

Is hamstrings injury an important issue in football (soccer)?

Yes, it is. Injury of the hamstrings is the most common injury type in football (12-16% of all injuries). Re-injury rate is relatively high and this should be taken into account in screening as well as during rehabilitation.

What is the mechanism of hamstrings injury?

From the video analysis studies, it appears that hamstring injuries usually occur during rapid acceleration, deceleration, change of direction or during the last part of the swing phase of gait. This phase is where hamstrings are working eccentrically.

Which are the main risk factors for hamstring injuries?

Although not clear, many factors are involved in the aetiology of the hamstrings injuries. These are grouped into intrinsic (age, previous injury history, fatigue etc) and extrinsic factors (lack or inappropriate warm-up, surface, temperature etc). There is strong evidence in the literature that players with advanced age and/or previous hamstrings injury are at a higher risk for hamstrings injury in the future. There might also be factors we still don’t know or we know very little involved in this type of injury occurrence.

Are low flexibility and large muscle imbalances associated with increased hamstring injury risk?

It is not clear so far. While some studies show a relationship between greater flexibility and lower injury risk others have failed to replicate these findings. The same holds for muscle imbalances. It is not to say that players do not need to improve their range of motion. It seems however, that above a threshold there is no additional protection for future injuries with improvements in flexibility.

Which is the recommended injury prevention programme by Prof Bahr and his team?

Prof Bahr and his group have done a lot of research on the Nordic exercise effect on hamstrings injury prevention. Their studies have shown that training the muscles regularly with this exercise has reduced the hamstrings injury occurrence.

Some details and recommendations for the programme

According to Prof Bahr it is important that the exercise is executed in the right way. Right execution of this exercise requires the coach to push the player downward at the start of exercise. At this stage the players execute resistance. Players should start with few repetitions once or twice a week and increase the training load and/or frequency progressively. Data have shown that players feel no pain the day after the Nordic exercise training provided the overload principle is followed.

Is Nordic exercise suitable for youth players?

Professor Bahr answered that although there is no related research, Nordic exercise could be used by 15 years and older players in order to better prepare them for the future training loads.

Some remarks

Nordic exercise is only an example of easy-to-use exercise for hamstrings injuries prevention. Strength & conditioning coaches should follow a holistic approach and bear in mind that players need to be trained for other muscle groups too. From the sports science perspective, fitness training for injury prevention should take into account, among others, the:

Injury history each player

Individual characteristics

Take-home messages (by the blog owner)

Nordic exercise is a good tool for hamstrings injury prevention. Coaches should follow a holistic approach and include evidence-based exercises that fit the group and the individual needs.

2 comments:

I'm glad you mentioned screening in an otherwise very good article. I was wondering if you have any thoughts on the work of Gray Cook and his team with the Function Movement Screen (FMS)and its effectiveness as far as predicting injury? The data over the last decade or so has shown that below at total score of 14 on the screen, the athlete has an approximate 2.5 times more risk of injury in the next 2 or 3 years, than someone with a higher score. It has proven true at multiple levels including the NFL, collegiate athletes, and sects of the military as well as the general public. There isn't too much data for soccer players...

With this write-up, people will now get a better understanding of Hamstrings. It is important that individuals have their own knowledge too as this can shield them from possible medical negligence from professionals.